1-substituted-2-(3-amino-1-propynyl)pyrrolidine derivatives

ABSTRACT

Compounds of the formula: ##STR1## pharmaceutical compositions containing the compounds and methods of using the compounds in the treatment of central cholinergic disfunction in a mammal are disclosed.

BACKGROUND OF THE INVENTION

The present invention relates to novel (3-amino-1-propynyl)pryrrolidinecompounds, pharmaceutical compositions containing the compounds and tothe use of the compounds for the treatment of central cholinergicdisfunction.

Senile Dementia of the Alzheimer's Type (SDAT) is a neurodegenerativedisease which results in the progressive impairment of memory.Post-mortem autopsies of brain tissue from SDAT patients have shown amarked decrease in cholinergic neurons. Taken together theseobservations form the basis for the cholinergic hypothesis for memoryloss. A series of chemical synthesis projects have been initiated in thegeriatric program to discover selective cholinergic agonists toameliorate the symptoms of this degenerative disease.

In this respect, a number of derivatives of the cholinergic agent,oxotremorine, have been synthesized. Resul, B. and coworkers, Eur. J.Med. Chem., 1982, 17, 317 report the synthesis ofN-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl) acetamide, referred to asBM-5, which acts as an antagonist at some muscarinic sites while beingan agonist at most others. It has been suggested that this type ofcompound may be useful for the therapy of Alzheimer - type dementia.Lundkvist, J. R. M., et al., J. Med. Chem., 1989, 32, 863-869synthesized a series of conformationally restricted analogues of BM-5which differ structurallY from those of the present invention.

SUMMARY OF THE INVENTION

This invention is concerned with new compounds described by thefollowing formulas: ##STR2## wherein A is selected from hydrogen, (C₁-C₆)acyl, (C₁ -C₆)alkoxycarbonyl, trihaloacetyl or (C₁-C₆)alkylsulfonyl; NR''' is equal to NR' and NR''; NR' is equal topyrrolidino, piperidino, amino, (C₁ -C₆)alkylamino, or (C₁-C₆)dialkylamino; NR'' is equal to (C₁ -C₆)trialkylamino; with theproviso that when NR' is equal to pyrrolidino or dimethylamino or whenNR'' is equal to trimethylamino, A may not be acetyl. The invention isalso concerned with methods of treating diseases of the central nervoussystem in mammals employing these new compounds; with pharmaceuticalpreparations containing these compounds; and with the processes for theproduction of these compounds.

DESCRIPTION OF THE INVENTION

The novel compounds of the present invention may be prepared inaccordance with the following schemes, wherein A is selected fromhydrogen, (C₁ -C₆)-acyl, (C₁ -C₆)alkoxycarbonyl, trihaloacetyl or (C₁-C₆)alkyl-sulfonyl; NR''' is equal to NR'' and NR'; NR' is equal topyrrolidino, piperidino, amino, (C₁ -C₆)alkylamino, or (C₁-C₆)dialkylamino; NR'' is equal to (C₁ -C₆)trialkylamino; with theproviso that when NR' is equal to pyrrolidino or dimethylamino or whenNR'' is equal to trimethylamino, A may not be acetyl.

Scheme 1 illustrates the synthesis of the derivatives with the (R)absolute configuration. ##STR3##

In accordance with Scheme I, N-α-t-BOC-D-proline 2a is reacted in anether solvent such as tetrahydrofuran at a temperature ranging from -2°C. to the reflux temperature of the solvent with 10M borane-methylsulfide complex to produce (R)-2-(hydroxymethyl)-1pyrrolidinecarboxylicacid, 1,1-dimethylethyl ester 3a. Compound 3a in a chlorinatedhydrocarbon solvent such as methylene chloride is treated with anoxidizing agent such as pyridinium chlorochromate, 4Å molecular sievesand glacial acetic acid to give (R)-2-formyl-1-pyrrolidinecarboxylicacid 1,1-dimethylethyl ester 4a. Compound 4a in methylene chloride istreated with a methylene chloride solution of triphenylphosphine andcarbon tetrabromide to produce(R)-2-(2,2-dibromoethenyl)-1pyrrolidinecarboxylic acid,1,1-dimethylethyl ester 5a. The dibromo compound 5a in an ether solventsuch as tetrahydrofuran is reacted at -78° C. with an alkyl lithiumreagent such as sec-butyllithium to give(R)-2-ethynyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester 6a.

The compound of general formula 6a is reacted with paraformaldehyde,acetic acid, copper (I) or (II) chloride and a secondary amine such aspyrrolidine in an ether solvent such as dioxane under an inertatmosphere at the reflux temperature of the solvent to give, onbasification, compounds of the general formula 7a. The compound ofgeneral formula 7a is reacted with a solution of a strong acid such as2N hydrochloric acid in an alcohol solvent at or around room temperatureto produce a compound of general formula 8a, for example(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine, dihydrochloride.

The compound of general formula 8a in methylene chloride is treated witheither a trihaloacetyl anhydride or chloride, a (C₁ -C₆)acyl anhydrideor chloride, a (C₁ -C₆)alkyl chloroformate, (C₁ -C₆)alkylsulfonylchloride or a mixed formyl acyl anhydride to produce a compound ofgeneral formula 9a, for example(R)-2-[3(1-pyrrolidinyl)-1-propynyl]-1-(trifluoroacetyl) pyrrolidine,hydrochloride.

Scheme II illustrates the synthesis of derivatives with the (S) absoluteconfiguration. ##STR4##

In accordance with Scheme II, proline methyl ester, hydrochloride 11b inmethylene chloride is treated with di-tert-butyl dicarbonate in thepresence of triethylamine using the method described by B. D. Harris, K.L. Bhat and M. M. Soulie, Heterocycles, 24, 1045 (1986) toproduce(S)-1-(1,1-dimethylethyl)-1,2- pyrrolidinecarboxylic acid,2-methyl ester 12b. Following the procedure in the above reference,compound 12b in tetrahydrofuran is reacted with lithium chloride andsodium borohydride in ethanol to produce (S)-2-(hydroxymethyl)-1pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester 3b.The remaining (S) compounds are made following Scheme I (b), (c), (d),(e), (f) and (g).

Alternately, in accordance with Scheme II compounds of general formula1b are prepared in a similar manner to those of general formula 1a usingN-α-t-Boc-L-proline as the starting compound with the proceduresdescribed in Scheme I.

The novel compounds described herein are useful as cholinergic agents. Achronic deficiency in central cholinergic function has been implicatedin a variety of neurologic and psychiatric disorders, including SenileDementia of the Alzheimer's type (SDAT), tardive dyskinesia, Pick'sdisease and Huntington's chorea. Postmortem neurochemical investigationsof patients with SDAT have demonstrated a reduction in presynapticmarkers for acetylcholine-utilizing neurons in the hippocampus and thecerebral cortex. [P. Davies and A. J. R. Maloney, Lancet, 1976-II, 1403,(1976); E. K. Perry, R. H. Perry, G. Blessed, B. E. Tomlinson, J.Neurol. Sci., 34, 247, (1976)]. The basis for this cholinergicabnormality is unclear, but evidence suggests that the cholinergicneurons in the nucleus basalis of Meynert may selectively degenerate inSDAT [J. T. Coyle, D. J. Price, M. R. DeLong, Science, 219, 1184,(1983)]. If this degeneration plays a role in behavior symptoms of thedisease, then a possible treatment strategy would be to compensate forthe loss of cholinergic output to the cortex and hippocampus.

In an aged monkey animal model, designed to mimic the symptoms of SDAT,the direct muscarinic agonists arecoline [R. T. Bartus, R. L. Dean, B.Beer, Neurobiology of Aging, 1, 145, (1980)] and oxotremorine [R. T.Bartus, R. L. Dean, B. Beer, Psychopharmacology Bulletin, 19, 168,(1983)] produced significant improvement in performance. These resultsin aged monkeys were corroborated in SDAT patients with arecoline whichproduced a more-consistent improvement when compared to theanticholinesterase inhibitor physostigmine [J. E. Christie, A. Shering,J. Ferguson, A. M. Glen, British Journal of Psychiatry, 138, 46,(1981)].

These animal behavioral and clinical results have instigated significantefforts in a search for a muscarinic agonist which will selectivelycompensate for the loss of cholinergic input in the hippocampus andcerebral cortex. However, the search must be refined to seek agonistswhich will not affect significantly the remaining body cholinergicfunctions thereby avoiding untoward side effects. The recent disclosure(T. I. Bonner, N. J. Buckley, A. C. Young, M. R. Brann, Science,237,527, (1987)] that muscarinic receptors are not all the same butexist as a heterogenous population of receptors substantiates thepossibility for the discovery of a selective muscarinic agonist.

N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide (BM-5) has beenreported to be a presynaptic cholinergic antagonist (which shoulddisinhibit the release of endogenous acetylcholine) and a postsynapticpartial cholinergic agonist (which should mimic the effects ofacetylcholine). ##STR5##

Chemically BM-5 (I) is a fairly flexible molecule that can assume anumber of different conformations. The present invention describes thesynthesis of a series of1-substituted-2-(3-amino-1-propynyl)pyrrolidines which are derivativesof BM-5 in which one degree of freedom (bond c) has been restricted.Generalization of structure (II) provides (III) which represents thetarget compounds of this invention; ##STR6##

The compounds of this invention were tested for cholinergic activityaccording to the following procedures.

[³ H] Quinuclidinyl Benzilate Binding Assay

This assay is utilized in conjunction with the ³ H-Cismethyldioxolanebinding assay to evaluate antagonist and high affinity agonist bindingproperties of CNS cholinergic agents. The procedure is adapted fromWatson, M., Yamamura, H. I., and Roeske, W. R., J. Pharmacol. Exp. Ther.237: 411-418 (1986) and Watson, M., Roeske, W. R., and Yamamura, H. I.,J. Pharmacol. Exp. Ther. 237: 419-427 (1986).

Tissue Preparation

Rats are sacrificed by decapitation and the brain removed and placed onice. The cerebral cortex is dissected on a cold stage, weighed andhomogenized (Polytron, setting 5.5 with PT-10 saw-tooth generator for 15seconds) in 50 volumes (wet wt/vol) of ice-cold 10 mM (8.1 mM Na₂ HPO₄,1.9 mM KH₂ PO₄) sodium-potassium phosphate buffer (NaKPB), pH 7.4. Thehomogenate is placed in an ice bath for 30 seconds and homogenized againas above. This procedure is repeated once again for a total of threetimes. The resulting homogenate is then diluted 1:3000 (original wetwt/vol) with ice-cold NaKPB for use in the assay. The final proteincontent per 2.0 ml of incubation mixture is 0.1 mg.

Dilution of Compounds

A stock solution of atropine is prepared at 0.2 mM to definenon-specific binding (1 μM final conc). Test compounds are prepared at40 mM (final conc 1 mM) in buffer (if water soluble) or in absoluteethanol - 1 N HCl (1:1, v/v) and serially diluted to the desiredconcentrations. In general, dose-response profiles are examined between1 mM and 1pM final concentrations.

Preparation of ³ H-QNB

³ H-QNB (NEN, NET-656; specific activity=30.0 Ci/mmol) is diluted to 5nM, with NaPB (final concentration=-0.25 nM activity approximately18,000 cpm at a counting efficiency of 55%).

³ H-QNB Binding Assay

A typical protocol is outlined below:

    ______________________________________                                  Test                                  Com-                   Buffer  Atropine                                  pound .sup.3 H-QNB                                               Tissue    Tube No.           ID*     μL   μL  μL μL  ml    ______________________________________    1-2    Total   50      --     --    100    1.85    3-4    NS      40      10     --    "      "    5-6    4e-11   --      --     50    "      "    7-8    4e-10   --      --     "     "      "     9-10  4e-09   --      --     "     "      "    11-12  4e-08   --      --     "     "      "    13-14  4e-07   --      --     "     "      "    15-16  4e-06   --      --     "     "      "    17-18  4e-05   --      --     "     "      "    19-20  4e-04   --      --     "     "      "    21-22  4e-03   --      --     "     "      "    23-24  4e-02   --      --     "     "      "    ______________________________________     *Stock concentration [M] of compound to be tested.

Components are added in the following order: test compound, radioligand,buffer or tissue to give a final volume of 2.0 ml. After adding thetissue homogenate, the tubes are thoroughly mixed and incubated at 25°C. for 120 minutes. At the end of 120 minutes, the samples are filteredthrough GF/B glass fiber filters (Whatman) using a 24 sample cellharvester (Brandel) under a vacuum of 15 mm Hg. The tubes are washedwith 5×3 ml ice-cold NaKPB. The filters are then placed in scintillationvials with 10 ml of scintillation cocktail (Beckman HP or HP/B), allowedto stand overnight, shaken and then counted. Specific binding iscalculated as Total - NS (non-specific). The percent inhibition ofspecific binding is then calculated and the IC50 values computed usingeither the LIGAND or LUNDON software packages for competition binding.The results of this test on representative compounds of this inventionappear in Table 1.

[³ H]-Cis-methyldioxolane (³ H-CD) Binding Assay (High Affinity)

This assay is utilized in conjunction with ³ H-QNB binding to evaluatehigh affinity agonist binding and antagonist properties of CNScholinergic agents. The procedure is adapted from Vickroy, T. W.,Roeske, W. R, and Yamamura, H. I, J. Pharmacol. Exp. Ther. 229: 747-755(1984). This is a rapid filtration assay that is set up to label onlythe high affinity agonist conformation of the muscarinic cholinergicreceptor.

Tissue Preparation

Rats are sacrificed by decapitation and the brain removed and placed onice. The cerebral cortex is dissected on a cold stage, weighed andhomogenized (Polytron, setting 5.5 with Pt-10 saw-tooth generator for 15seconds in 50 volumes (wet wt/vol) of ice-cold 10 mM (8.1 mM Na₂ HPO₄,1.9 mM KH₂ PO₄) sodium-potassium phosphate buffer (NaKPB), pH 7.4. Thehomogenate is placed in an ice bath for 30 seconds and homogenized againas above. This procedure is repeated once again for a total of threetimes. The resulting homogenate is then diluted 1:300 (original wetwt/vol) with ice-cold NaKPB for use in the assay. The final proteincontent per 2.0 ml of incubation mixture is 0.75 mg.

Dilution of compounds

A stock solution of atropine is prepared at 0.2 mM to definenon-specific binding 11M final conc). Test compounds are prepared at 40mM (final conc 1 mM) in buffer (if water soluble) or in absoluteethanol - 1N HCl (1:1, v/v) and serially diluted to the desiredconcentrations. In general, dose-response profile are examined between 1mM and 1 pM final concentrations.

Preparation of ³ H-CD

³ H-CD (NEN, NET-647; specific activity=55.5 Ci/mmol) is diluted to 20nM with NaPB (final conc=1.0 nM, activity approximately 75,000 cpm at acounting efficiency of 55%).

Technical Notes

³ H-CD adheres readily to both glass and plastic surfaces. To eliminatethis problem (and the chance for introducing artifacts into theresults), stock vials, pipette tips and all glass tubes are routinelytreated with Prosil-28, a siliconizing agent, and oven dried prior touse in an assay. Additionally, the GF/B glass fiber filters arepre-soaked in an aqueous polyethylenimine (PEI) solution (0.1%, pH 7.0)prior to use.

All points in the inhibition curve (including total and non-specificbinding)are always measured on single PEI treated filter strips tominimize filter-to-filter variability. (See Bruns, R. F., et al. Anal.Biochem. 132: 74-81 (1983) for the use of PEI treated filters infiltration receptor assays).

The ³ H-CD is prepared fresh in buffer just prior to use in the assay toavoid possible decomposition. It should be kept on an ice bath afterdilution in buffer.

³ H-CD Binding Assay

A typical protocol is outlined below:

    ______________________________________                                  Test                                  Com-                   Buffer  Atropine                                  pound .sup.3 H-CD                                               Tissue    Tube No.           ID*     μL   μL  μL μL  ml    ______________________________________    1-2    Total   50      --     --    100    1.85    3-4    NS      40      10     --    "      "    5-6    4e-11   --      --     50    "      "    7-8    4e-10   --      --     "     "      "     9-10  4e-09   --      --     "     "      "    11-12  4e-08   --      --     "     "      "    13-14  4e-07   --      --     "     "      "    15-16  4e-06   --      --     "     "      "    17-18  4e-05   --      --     "     "      "    19-20  4e-04   --      --     "     "      "    21-22  4e-03   --      --     "     "      "    23-24  4e-02   --      --     "     "      "    ______________________________________     *Stock concentration [M] of compound to be tested.

Components are added in the following order: compound, radioligand,buffer or tissue to give a final volume of 2.0 ml. After adding thetissue homogenate, the tubes are thoroughly mixed and incubated at 25°C. for 120 minutes. At the end of 120 minutes, the samples are filteredthrough PEI pretreated GF/B glass fiber filters (Whatman) using a 24sample cell harvester (Brandel) under a vacuum of 15 mm Hg. The tubesare washed with 5×3 ml ice-cold NaKPB. The filters are then placed inscintillation vials with 10 ml of scintillation cocktail (Beckman HP orHP/B), allowed to stand overnight, shaken and then counted. Specificbinding is calculated as Total - NS (non-specific). The percentinhibition of specific binding is then calculated and the IC50 valuescomputed using either the LIGAND or LUNDON software packages forcompetition binding. The results of this test on representativecompounds of this invention appear in Table I.

                  TABLE I    ______________________________________                       .sup.3 H-QNB                                  .sup.3 H-CD    Compound           IC.sub.50 μM                                  IC.sub.50 nM    ______________________________________    (R)-2-[3-(1-Pyrrolidinyl-1-                       34         3,583    propynyl]-1-pyrrolidinecar-    boxaldehyde    (S)-2-[3-(1-Pyrrolidinyl)-1-                       65         5,235    propynyl]-1-pyrrolidinecar-    boxaldehyde    (S)-2-[3-(1-Pyrrolidinyl)-1-                       88         11,077    propynyl]-1-pyrrolidinecar-    boxaldehyde, hydrochloride    (R)-1-Acetyl-2-[3-(1-pyrroli-                       8.8        780    dinyl)-1-propynyl]pyrrolidine    (S)-1-Acetyl-2-[3-(1-pyrroli-                       76         2,713    dinyl)-1-propynyl]pyrrolidine    (S)-1-Acetyl-2-[3-(1-pyrroli-                       73         3,262    dinyl)-1-propnyl]pyrrolidine,    hydrochloride    (R)-1-[3-(2-Pyrrolidinyl)-2-                       3.1        514    propynyl]pyrrolidine    (R)-1-[3-(2-Pyrrolidinyl)-2-                       2.7        742    propynyl]pyrrolidine,    dihydrochloride    (S)-2-[3-(1-Pyrrolidinyl)-1-                       18         5,473    propynyl]-1-(trifluoroacetyl)-    pyrrolidine    (S)-2-[3-(1-Pyrrolidinyl)-1-                       16         3,834    (trifluoroacetyl)pyrrolidine,    hydrochloride    (R)-1-(Methylsulfonyl)-2-[3-(1-                       23         973    pyrrolidinyl)-1-propynyl]-    pyrrolidine    (R)-1-(Methylsulfonyl)-2-[3-(1-                       25         2,448    pyrrolidinyl)-1-propynyl]-    pyrrolidine, hydrochloride    (S)-1-(Methylsulfonyl)-2-[3-(1-                       43         6,784    pyrrolidinyl]-1-propynyl]-    pyrrolidine    (S)-1-(Methylsulfonyl)-2-[3-(1-                       47         8,078    pyrrolidinyl)-1-propynyl]-    pyrrolidine, hydrochloride    (R)-2-[3-(1-Pyrrolidinyl)-1-                       6.5        29    propynyl]-1-pyrrolidinecar-    boxylic acid, 1,1-dimethyl-    ethyl ester    (S)-2-[3-(1-Pyrrolidinyl)-1-                       4.2        247    propynyl]-1-pyrrolidinecar-    boxylic acid, 1,1-dimethyl-    ethyl ester    (R)-2-[3-(1-Pyrrolidinyl)-1-                       40         2,577    propynyl]-1-(trifluoroacetyl)-    pyrrolidine    (R)-2-[3-(1-Pyrrolidinyl)-1-                       43         8,571    propynyl]-1-(trifluoroacetyl)-    pyrrolidine, dihydrochloride    ______________________________________

Those compounds which have ³ H-CD IC₅₀ values of <1000 nM and/or ³ H-QNBIC₅₀ values of <1000 uM are considered active. Those substituents whichshow weak activity or are inactive by these criteria may be consideredpro-drugs for the more active substituents.

The pharmaceutical preparations of the present invention may contain,for example, from about 0.5% up to about 90% of the active ingredient incombination with the carrier, more usually between 5% and 60% by weight.

The effective dosage of active ingredient employed may vary with theparticular compound employed, the mode of administration, and theseverity of the condition being treated. In general, however,satisfactory results are obtained when the compounds of the inventionare administered at a daily dosage of from about 0.02 mg to about 100mg/kg of patient body weight, preferably given in divided doses two tofour times a day, or in sustained release form. For most patients, thetotal daily dosage is from about 1 mg to about 5,000mg, preferably fromabout 1 mg to 20 mg. Dosage forms suitable for internal use comprisefrom about 0.25 to 5.0 mg of the active compound in intimate admixturewith a solid or liquid pharmaceutically acceptable carrier. This dosageregimen may be adjusted to provide the optimal therapeutic response. Forexample, several divided doses may be administered daily or the dose maybe proportionally reduced as indicated by the exigencies of thetherapeutic situation.

A decided practical advantage is that these active compounds may beadministered orally as well as by intravenous, intramuscular, orsubcutaneous routes if necessary. Solid carriers include starch,lactose, dicalcium phosphate, microcrystalline cellulose, sucrose, andkaolin, while liquid carriers include sterile water, polyethyleneglycols, non-ionic surfactants, and edible oils such as corn, peanut,and sesame oils, as are appropriate to the nature of the activeingredient and the particular form of administration desired. Adjuvantscustomarily employed in the preparation of pharmaceutical compositionsmay be advantageously included, such as flavoring agents, coloringagents, and antioxidants, e.g., vitamin E, ascorbic acid, BHT and BHA.

The preferred pharmaceutical compositions from the standpoint of ease ofpreparation and administration are solid compositions, particularlytablets and hard-filled or liquid-filled capsules. Oral administrationof the compounds is preferred.

These active compounds may also be administered parenterally orintraperitoneally. Solutions or suspensions of these active compounds asa free base or pharmacologically acceptable salt can be prepared inwater suitably mixed with a surfactant such as hydroxypropylcellulose.Dispersions can also be prepared in glycerol, liquid polyethyleneglycols, and mixtures thereof in oils. Under ordinary conditions ofstorage and use, these preparations contain a preservative to preventthe growth of microorganisms.

The pharmaceutical forms suitable for injectable use include sterileaqueous solutions or dispersions and sterile powders for theextemporaneous preparation of sterile injectable solutions ordispersions. In all cases, the form must be sterile and must be fluid tothe extent that easy syringability exits. It must be stable under theconditions of manufacture and storage and must be preserved against thecontaminating action of microorganisms such as bacteria and fungi. Thecarrier can be a solvent or dispersion medium containing, for example,water, ethanol, polyol (e.g., glycerol, propylene glycol, and liquidpolyethylene glycol), suitable mixtures thereof, and vegetable oils.

As used herein, "pharmaceutically acceptable carrier" includes any andall solvents, dispersion media, coatings, antibacterial and antifungalagents, isotonic and absorption delaying agents and the like. The use ofsuch media and agents for pharmaceutically active substances is wellknown in the art. Except insofar as any conventional media or agent isincompatible with the active ingredient, its use in therapeuticcompositions is contemplated.

The following examples describe in detail the chemical synthesis ofrepresentative compounds of the present invention. The procedures areillustrations, and the invention should not be construed as beinglimited by chemical reactions and conditions they express. No attempthas been made to optimize the yields obtained in these reactions, and itwould be obvious to one skilled in the art that variations in reactiontimes, temperatures, solvents, and/or reagents could increase theyields.

EXAMPLE 1 (R)-2-(Hydroxymethyl)-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester

To a solution of 25.0 g of N-α-t-DOC-D-proline in 250 ml oftetrahydrofuran which is cooled to 0° C. is added dropwise 15 ml of 10Mborane-methyl sulfide complex. The reaction is kept at around -20° C.during the addition followed by warming to room temperature and then isgently refluxed for one hour. The mixture is cooled to 0° C., 250 ml ofmethanol is added carefully and the reaction is evaporated in vacuo togive 23.3 g of a colorless oil which crystallizes on standing to acolorless solid, mp 50°-53° C., [α]_(D) ²⁶° =+47°±1 (C=1.162%, methylenechloride).

EXAMPLE 2 (R)-2-Formyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethylester

To a water cooled (25° C.) solution of 10.0 g of(R)-2-(hydroxymethyl)-1-pyrrolidinecarboxylic acid, 1,1-dimethylethylester in 250 ml of dry methylene chloride is added in one portion 16.0 gof pyridinium chlorochromate, 36.0 g of dried, crushed 4Å molecularsieves and 4.5 ml of glacial acetic acid. The resulting mixture isstirred at 25° C. for one hour. Twenty-five grams of diatomaceous earthand 500 ml of diethyl ether is added, the suspension is filtered througha pad of diatomaceous earth and the filtrate concentrated in vacuo. Theresidue is dissolved in diethyl ether and is passed through a shortcolumn of silica gel using diethyl ether as the eluant. The first two500 ml fractions contain the desired aldehyde. The solvent isconcentrated in vacuo to give 10.1 g of desired product.

EXAMPLE 3 (R)-2-(2,2-Dibromoethenyl)-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester

To a solution of 40.0 g of triphenylphosphine and 26.0 g of carbontetrabromide in 700 ml of dry methylene chloride, which is cooled to 0°C., is added dropwise a solution of 10.1 g of(R)-2-formyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester in 20ml of dry methylene chloride. The reaction is stirred for 30 minutes, asolution of saturated aqueous sodium bicarbonate is added and the layersare separated. The organic layer is filtered and concentrated in vacuo.The residue is chromatographed using silica gel as absorbant to give10.0 g of the product as colorless crystals, mp 55°-60° C., [α]_(D) ²⁶°=-22°±1 (C=1.149%, methylene chloride).

EXAMPLE 4 (R)-2-Ethynyl-1-pyrrolidinecarboxxylic acid, 1,1-dimethylethylester

A solution of 7.0 g of(R)-2-(2,2-dibromo-ethenyl)-1-pyrrolidinecarboxylic acid,1,1-dimethyl-ethyl ester in 75 ml of dry tetrahydrofuran is cooled to-78° C. under an atmosphere of argon and treated with 33.1 ml ofsec-butyllithium over 45 minutes. The resulting solution is stirred at-78° C. for one hour. The reaction mixture is treated with 100 ml ofsaturated ammonium chloride, warmed to room temperature, diluted with300 ml of diethyl ether and the layers are separated. The organic layeris washed with 150 ml of saturated sodium chloride, dried over sodiumsulfate and concentrated in vacuo. A 0.72 g aliquot of the product ispurified by chromatography using silica gel as absorbant to give 0.55 gof the product as a colorless oil, [α]_(D) ²⁶° =+84°±1 (C=1.049%,methylene chloride).

EXAMPLE 5 (R)-2-[3-(1-Pyrrolidinyl)-1-propynyl]-1-pyrrolidine-carboxylicacid, 1,1-dimethylethyl ester

A mixture of 3.5 g of (R)-2-ethynyl-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester, 75 ml dry dioxane, 3.0 ml pyrrolidine, 1.43 gof paraformaldehyde, 7.0 ml of glacial acetic acid and 50 mg of cuprouschloride is stirred at room temperature for 15 minutes then refluxed for2 hours. The reaction is cooled and concentrated in vacuo. The residueis partitioned between water and methylene chloride and the pH of themixture is adjusted to pH 11 with ammonium hydroxide. The basifiedreaction is extracted with methylene chloride and dried over sodiumsulfate. The methylene chloride solution is passed over hydrousmagnesium silicate and concentrated in vacuo to give 5.65 g of a darkyellow oil. The product is purified by chromatography using deactivatedalumina as the absorbant, to give 0.55 g of the product as a pale yellowoil, [α]_(D) ²⁶° =+100.6°±0.8 (C=1.22%, methylene chloride).

EXAMPLE 6 (R)-1-[3-(2-Pyrrolidinyl)-2-propynyl] pyrrolidine,dihydrochloride

A mixture of 7.0 g of (R)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester, 61 ml of ethanol and 61 ml of 2N hydrochloricacid is heated at 80° C. for one hour. The reaction is concentrated invacuo and the residue is extracted with methylene chloride. The aqueouslayer is concentrated in vacuo, made basic with 10N sodium hydroxide andextracted with methylene chloride. The methylene chloride solution isdried over sodium sulfate, filtered and concentrated in vacuo. Theresidue is dissolved in methanol, treated with an excess of methanolichydrogen chloride and precipitated with the addition of diethyl ether.The dihydrochloride is recrystallized from hot methanol to give pureproduct, mp 198°-200° C. with decomposition, [α]_(D) ²⁶° =+21°±1(C=1.012%, methanol).

EXAMPLE 7(R)-2-3-(1-Pyrrolidinyl)-1-propynyl]1-(trifluoroacetyl)pyrrolidine,hydrochloride

To a solution of 0.63 g of(R)-1-[3-(2-pryrrolidinyl)-2-propynyl]pyrrolidine in 10 ml of methylenechloride which is cooled to 0° C. is added 2.0 ml of trifluoroaceticanhydride. The reaction is stirred at room temperature for 2 hours,treated with 5 ml of methanol, washed with sodium bicarbonate and driedover sodium sulfate. The organic layer is passed over a thin pad ofhydrous magnesium silicate and the filtrate is concentrated in vacuo.The residue is treated with an excess of methanolic hydrogen chlorideand the product is precipitated by the addition of ether to give theproduct as colorless crystals, mp 156°-157° C., [α]_(D) ²⁶° =+103°±1(C=1.160%, methanol).

EXAMPLE 8 (R)-1-Acetyl-2-[3-(1-pyrrolidinyl)-1-propynyl]-pyrrolidine,hydrochloride

Following the procedure of Example 7, 0.63 g of(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine in 10 ml of methylenechloride is treated with 1.33 ml of acetic anhydride. The hydrochloridesalt of the product is obtained as a yellow oil, [α]_(D) ²⁶° =+85°±1(C=1.137%, methanol.

EXAMPLE 9(R)-1-(Methylsulfonyl)-2-[3-(1-pyrrolidinyl)-1-propynyl]pyrrolidine,hydrochloride

Following the procedure of Example 7, 0.65 g of(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine in 5 ml of methylenechloride is treated with 0.31 ml of methanesulfonyl chloride. Theproduct is purified by chromatography using deactivated alumina as theabsorbant to give the product as colorless crystals. The hydrochloridesalt of the product is obtained as colorless crystals, mp 198°-199° C.(dec), [α]_(D) ²⁶° =+78°±1 (C=1.020%, methanol).

EXAMPLE 10(R)-2-(3-(1-Pyrrolidinyl)-1-propynyl]-1-pyrrolidine-carboxaldehyde

To a solution of 0.58 g of(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine in 6.9 ml of formicacid is added dropwise at room temperature 2.3 ml of acetic anhydride.The reaction is stirred for 30 minutes, followed by the addition of 10ml of ice water. The resulting mixture is concentrated in vacuo and theresidue treated with a solution of saturated sodium bicarbonate. Theaqueous layer is extracted with methylene chloride, dried over sodiumsulfate and concentrated in vacuo to a yellow oil. The product ispurified by chromatography using deactivated alumina as the absorbant togive 0.65 g of a light yellow oil, [α]_(D) ²⁶° =+99°±1 (C=1.008%,methylene chloride).

EXAMPLE 11 (S)-1-(1,1-Dimethylethyl)-1,2-pyrrolidinecarboxylic acid,2-methyl ester

Following the procedure of B. D. Harris, K. L. Bhat and M. M. Soulie,Heterocycles, 24, 1045 (1986), 36.9 g of L-proline methyl esterhydrochloride, 62 ml of triethyl amine, 61 ml of di-tert-butyldicarbonate and 250 ml of methylene chloride is reacted to give 42 g ofthe desired product as an oil, [α]_(D) ²⁶° =-58°±1 (C=1.125%,chloroform). Literature rotation [α]_(D) ²⁶° =-54°±1 (C=3.67%,chloroform).

EXAMPLE 12 (S)-2-(Hydroxymethyl)1-pyrrolidinecarboxvlic acid,1,1-dimethylethyl ester

Following the procedure of B. D. Harris, K. L. Bhat, and M. M. Soulie,Heterocycles, 24, 1045 (1986), 6.83 g of lithium chloride, 6.09 g ofsodium borohydride pellets, 115 m. of ethanol and 18.4 g of(S)-1-(1,1-dimethylethyl)1,2-pyrrolidinecarboxylic acid, 2-methyl esterin 80 ml of tetrahydrofuran is reacted to give 14.0 g of the desiredproduct as white crystals, mp 58°-59° C., [α]_(D) ²⁶° =-50°±1 (C=1.05%,chloroform). Literature rotation [α]_(D) ²⁶° =-48°±1 (C=1.2,chloroform).

EXAMPLE 13 (S)-2-Formyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethylester

Following the procedure of Example 2, 16.0 g of pyridiniumchlorochromate, 10.0 g of (S)-2-(hydroxymethyl)-1-pyrrolidinecarboxylicacid, 1,1-dimethylethyl ester, 36.0 g of crushed 4Å molecular sieves and4.5 ml of glacial acetic acid in 250 ml of methylene chloride gives 6.8g of the product as a yellow oil.

EXAMPLE 14 (S)-2-(2,2-Dibromoethenyl-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester

Following the procedure of Example 3, 6.8 g of(S)-2-formyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester in 20ml of methylene chloride is reacted with 40 g of triphenylphosphine, 26g of carbon tetrabromide in 700 ml of methylene chloride to give 5.8 gof the desired product as a colorless solid, mp 58°-59° C., [α]_(D) ²⁶°=+24°±1 (C=1.048%, methylene chloride).

EXAMPLE 15 (S)-2-Ethynyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethylester

Following the procedure of Example 4, 10.0 g of(S)-2-(2,2-dibromoethenyl)-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester in 150 ml of dry tetrahydrofuran, is reactedwith 45.5 ml of sec-butyl-lithium to give 3.0 g of the product as ayellow oil, [α]_(D) ²⁶° =-81°±1 (C=0.974%, methylene chloride).

EXAMPLE 16 (S)-2-[3-(1-Pyrrolidinyl)-1-propynyl]1-pyrrolidine-carboxylicacid, 1,1-dimethylethyl ester

Following the procedure of Example 5, a mixture of 5.30 g of(S)-2-ethynyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester,4.50 ml of pyrrolidine, 2.20 g of paraformaldehyde, 10.0 ml of glacialacetic acid, 0.10 g of cuprous chloride and 80 ml of dioxane is heatedto give 6.62 g of the product as a yellow oil, [α]_(D) ²⁶° =-100°±1(C=1.042 methylene chloride).

EXAMPLE 17 (S)-1-[3-(2-Pyrrolidinyl)-2-propynyl]pyrrolidine,dihydrochloride

Following the procedure of Example 6, a mixture of 6.62 g of(S)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,1,-dimethylethyl ester, 59.4 ml of 2N hydrochloric acid and 60 ml ofethanol is reacted to give 2.50 g of the product as colorless crystalsmp 196°-197° C. with decomposition, [α]_(D) ²⁶° =-20°±1 (C=1.047%,methanol).

EXAMPLE 18 (S)-2-[3-(1-Pyrrolidinyl)-1-propynyl]1-trifluoroacetyl)pyrrolidine, hydrochloride

Following the procedure of Example 7, a mixture of 0.71 g of(S)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine, 2.25 ml oftrifluoroacetic acid and 12 ml of methylene chloride is reacted to give0.81 g of the product as a pale yellow oil, [α]_(D) ²⁶° =-125°±1(C=1.098%, methylene chloride). A 0.30 g aliquot of the product istreated with an excess of methanolic hydrogen chloride. The resultingsalt is crystallized from methanol/ether to give 0.20 g of colorlesscrystals, mp 156°-157° C., ]α]_(D) ²⁶° =-102°±1 (C=1.030%, methanol).

EXAMPLE 19 (S)-1-Acetyl-2-[3-(1-pyrrolidinyl)-1-propynly]-pyrrolidine,hydrochloride

Following the procedure of Example 7, 0.71 g of(S)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine in 20 ml of methylenechloride is treated with 1.50 ml of acetic anhydride to give the productas a pale yellow oil, [α]_(D) ²⁶° =-117°±1 (C=1.031%, methylenechloride).The hydrochloride salt of the prod The hydrochloridic salt ofthe product is obtained as colorless crystals, [α]_(D) ²⁶° =-103°±1(C=1.060%, methanol).

EXAMPLE 20(S)-1-(Methylsulfonyl)-2-[3-(1-pyrrolidinyl)-1propynyl]pyrrolidine,hydrochloride

Following the procedure of Example 7, 0.58 g of(S)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine in 20 ml of methylenechloride is treated with 0.28 ml of methanesulfonyl chloride to give theproduct as a pale yellow oil, [α]_(D) ²⁶° =-81°±1 (C=1.136%, methanol).The hydrochloric salt of the product is obtained as colorless crystals,mp 198°-199° C., [α]_(D) ²⁶° =-85°±1 (C=1.129%, methylene chloride).

EXAMPLE 21(S)-2-[3-(1-Pyrrolidinyl)-1-propynyl]1-pyrrolidine-carboxaldehyde,hydrochloride

Following the procedure of Example 7, 1.30 g of(S)-1-[3-(2-pyrrolidinyl-2-propynyl]pyrrolidine in 15.5 ml of formicacid is treated with 5.2 ml of acetic anhydride to give the product as apale yellow oil, [α]_(D) ²⁶° =-126°±1 (C=1.71%, methylene chloride). Thehydrochloride salt of the product is obtained as a yellow oil, [α]_(D)²⁶° =-104°±1 (C=1.113%, methanol).

EXAMPLE 22 (R)-2-[3-(1-Pyrrolidinyl)-1-propynyl]1pyrrolidine-carboxylicacid, methyl ester

To a stirred solution of 0.60 g of(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine in 10 ml of ether isadded dropwise solutions of 0.35 g of methyl chloroformate in 5 ml ofether and 0.74 ml 5N sodium hydroxide. The reaction is stirred for 30minutes at 0° C. and diluted with ether. The organic layer is separatedand the aqueous layer is extracted with methylene chloride. The combinedmethylene chloride extracts are dried over sodium sulfate andconcentrated in vacuo to give 0.65 g of the crude product as a paleyellow oil. The residue is purified by column chromatography usingdeactivated alumina as absorbent to give 0.55 g of the product as a paleyellow oil, [α]_(D) ²⁶° =+112°±1 (C=1.011%, methylene chloride).

EXAMPLE 23(S)-2-[3-(1-Pyrrolidinyl)-1-propynyl]-1-pyrrolidine-carboxylic acid,methyl ester

Following the procedure of Example 22, a mixture of 0.05 g of(S)-1-[3-(2-pyrrolidinyl)-2-propynyl]-pyrrolidine, 0.29 g of methylchloroformate and 0.60 ml 5N sodium hydroxide in 15 ml of ether isreacted to give 0.50 g of the product as a pale yellow oil, [α]_(D) ²⁶°=-131°±1 (C=1.037%, methylene chloride).

EXAMPLE 24 (R)-2-3-(1-Pyrrolidinyl)-1-propynyl-1-pyrrolidine-carboxylicacid, ethyl ester

Following the procedure of Example 22, a mixture of 0.60 g of(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine 0.40 g of ethylchloroformate and 0.75 ml 5N sodium hydroxide in 15 ml of ether isreacted to give 0.62 g of the product as a pale yellow oil, [α]_(D) ²⁶°=+109°±1 (C=1.072, methylene chloride).

EXAMPLE 25(S)-2-[-(3-(1-Pyrrolidinyl)-1-propynyl]1-pyrrolidine-carboxylic acid,ethyl ester

Following the procedure of Example 22, a mixture of 0.5 g of(S)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine, 0.33 g of ethylchloroformate and 0.6 ml 5N sodium hydroxide in 15 ml of ether isreacted to give 0.5 g of the product as a pale yellow oil, [α]_(D) ²⁶°=-123°±1 (C=1.111%, methylene chloride).

We claim:
 1. A compound selected from those of the formula: ##STR7##wherein A is selected from hydrogen, (C₁ -C₆)acyl, (C₁ -C₆)alkoxycarbonyl, trihaloacetyl or (C₁ -C₆)alkylsulfonyl; NR''' is equalto NR' or NR''; NR' is pyrrolidino, piperidino, amino, (C₁-C₆)alkylamino, or (C₁ -C₆)dialkylamino; NR'' is (C₁ -C₆)trialkylamino;with the proviso that when NR' is pyrrolidino or dimethylamino or NR''is trimethylamino, A may not be acetyl.
 2. A compound selected from theformula: ##STR8## wherein A is selected from hydrogen, (C₁ -C₆)acyl, (C₁-C₆) alkoxycarbonyl, trinaloacetyl or (C₁ -C₆)alkylsulfonyl; NR''' isequal to NR' or NR''; NR'is pyrrolidino, piperidino, amino, (C₁-C₆)alkylamino, or (C₁ -C₆)dialkylamino; NR'' is (C₁ -C₆)trialkylamino;with the proviso that when NR' is pyrrolidino or dimethylamino or NR''is trimethylamino, A may not be acetyl.
 3. A compound selected from theformula: ##STR9## wherein A is selected from hydrogen, (C₁ -C₆)acyl, (C₁-C₆) alkoxycarbonyl, trihaloacetyl or (C₁ -C₆)alkylsulfonyl; NR''' isNR' or NR''; NR' is pyrrolidino, piperidino, amino, (C₁ -C₆)alkylamino,or (C₁ -C₆)dialkylamino; NR'' is (C₁ -C₆)trialkylamino; with the provisothat when NR' is pyrrolidino or dimethylamino or NR'' is trimethylamino,A may not be acetyl.
 4. A compound according to claim 1, wherein A isselected from hydrogen; NR''' is NR' or NR''; NR' is pyrrolidino,piperidino, amino, (C₁ -C₆)alkylamino, or (C₁ -C₆)dialkylamino; NR'' is(C₁ -C₆)trialkylamino.
 5. A compound according to claim 1, wherein A isselected from (C₁ -C₆)acyl; NR''' is NR' pr NR''; NR' is pyrrolidino,piperidino, amino, (C₁ -C₆)alkylamino, or (C₁ -C₆)dialkylamino; NR'' is(C₁ -C₆)trialkylamino; with the proviso that when NR' is pyrrolidino ordimethylamino or NR'' is (C₁ -C₆)trimethylamino, A may not be acetyl. 6.A compound according to claim 1 wherein A is selected from (C₁-C₆)alkoxycarbonyl; NR''' is NR' or NR''; NR' is pyrrolidino,piperidino, amino, (C₁ -C₆)alkylamino, or (C₁ -C₆)dialkylamino; NR'' is(C₁ -C₆)trialkylamino.
 7. A compound according to claim 1, wherein A isselected from trihaloacetyl; NR''' is NR' or NR''; NR' is pyrrolidino,piperidino, amino, (C₁ -C₆)alkylamino, or (C₁ -C₆)dialkylamino; NR'' is(C₁ -C₆)trialkylamino.
 8. A compound according to claim 1, wherein A isselected from (C₁ -C₆)alkylsulfonyl; NR''' is NR' or NR''; NR' ispyrrolidino, piperidino, amino, (C₁ -C₆)alkylamino, or (C₁-C₆)dialkylamino; NR'' is (C₁ -C₆)trialkylamino.
 9. The compoundaccording to claim 1,(R)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxaldehyde. 10.The compound according to claim 1,(S)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxaldehyde. 11.The compound according to claim 1,(R)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine.
 12. The compoundaccording to claim 1, (S)-1-[3-(2-pyrrolidinyl)-2-propynyl]pyrrolidine.13. The compound according to claim 1,(S)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-(trifluoroacetyl)pyrrolidine.14. The compound according to claim 1,(R)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-(trifluoroacetyl)pyrrolidine.15. The compound according to claim 1,(R)-1-(methanesulfonyl)-2-[3-(1-pyrrolidinyl)-1-propynyl]pyrrolidine.16. The compound according to claim 1,(S)-1-(methanesulfonyl)-2-[3-(1-pyrrolidinyl)-1-propynyl]pyrrolidine.17. The compound according to claim 1,(R)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester.
 18. The compound according to claim 1,(S)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,1,1-dimethylethyl ester.
 19. The compound according to claim 1,(R)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,methyl ester.
 20. The compound according to claim 1,(S)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,methyl ester.
 21. The compound according to claim 1,(R)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,ethyl ester.
 22. The compound according to claim 1,(S)-2-[3-(1-pyrrolidinyl)-1-propynyl]-1-pyrrolidinecarboxylic acid,methyl ester.
 23. A method of treating central cholinergic disfunctionin a mammal which comprises administering to said mammal an effectiveamount of a compound selected from those of claim
 1. 24. Apharmaceutical composition of matter comprising from about one mg toabout 500 mg of a compound selected from those of claim 1 in associationwith a pharmaceutically acceptable carrier.
 25. A pharmaceuticalcomposition according to claim 24 in unit dosage form.